Multi-use wireless power and data system

ABSTRACT

A wireless device is disclosed that includes an antenna system comprising at least one inductive element and two or more capacitive elements. A switching component configured to change a circuit configuration of the capacitive elements. A controller configured to transmit a signal using the antenna system and to receive a response from a first device, to determine a communications protocol associated with the first device and to change a configuration of the antenna system in response to the detected communications protocol by actuating the switching component.

RELATED APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication No. 62/031,027, filed Jul. 30, 2014, and U.S. patentapplication Ser. No. 14/798,700, filed Jul. 14, 2015, U.S. patentapplication Ser. No. 13/355,416, filed Jan. 20, 2012, and claims benefitof U.S. Provisional Application No. 61/434,622, filed Jan. 20, 2011,each of which is hereby incorporated by reference for all purposes as ifset forth herein in its entirety.

TECHNICAL FIELD

The present disclosure relates generally to power and data transferbetween two devices through a magnetic or radio frequency (RF)interface.

BACKGROUND OF THE INVENTION

Devices that are used for wirelessly transmitting data are typicallydesign to a predetermined standard for use with other devices that aredesigned to the same standard. Devices that are built to differentstandards cannot interact with each other.

SUMMARY OF THE INVENTION

A wireless device is disclosed that includes an antenna system that hasat least one inductive element and two or more capacitive elements. Aswitching component changes a circuit configuration of the capacitiveelements. A controller transmits a signal using the antenna system andreceives a response from a first device, to determine a communicationsprotocol associated with the first device and to change a configurationof the antenna system in response to the detected communicationsprotocol by actuating the switching component.

Other systems, methods, features, and advantages of the presentdisclosure will be or become apparent to one with skill in the art uponexamination of the following drawings and detailed description. It isintended that all such additional systems, methods, features, andadvantages be included within this description, be within the scope ofthe present disclosure, and be protected by the accompanying claims.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Aspects of the disclosure can be better understood with reference to thefollowing drawings. The components in the drawings are not necessarilyto scale, emphasis instead being placed upon clearly illustrating theprinciples of the present disclosure. Moreover, in the drawings, likereference numerals designate corresponding parts throughout the severalviews, and in which:

FIG. 1A is a diagram of a system for wireless power and datatransmission in accordance with an exemplary embodiment of the presentdisclosure;

FIG. 1B is a diagram of different exemplary topologies for protecting awireless power receiver from over-voltages using the de-tuning of theresonant circuit to keep the rectified voltage to safe levels;

FIG. 2 is a diagram of an exemplary circuit to protect a resonantwireless power receiver from over-voltages by shorting the coil to keepthe rectified voltage to safe levels;

FIG. 3 is a diagram of a system for providing a full-synchronous bridgeas a rectifier in wireless power circuits, in accordance with anexemplary embodiment of the present disclosure;

FIG. 4 is a diagram of current and timing waveforms, in accordance withan exemplary embodiment of the present disclosure;

FIG. 5 is a diagram of a system that is configured to resonate at twodifferent frequencies, in accordance with an exemplary embodiment of thepresent disclosure;

FIG. 6 is a diagram of a system with a step-down DC/DC switchingconverter, in accordance with an exemplary embodiment of the presentdisclosure;

FIG. 7 is a diagram of a system with a passive resonator that acts as arepeater in a magnetic resonant power transfer system, in accordancewith an exemplary embodiment of the present disclosure;

FIG. 8 is a diagram a class E transmitter, in accordance with anexemplary embodiment of the present disclosure;

FIG. 9 is a diagram of an AC current waveform generated by class Etransmitter;

FIG. 10A is a diagram of exemplary waveforms for receiver typedetection, in accordance with an exemplary embodiment of the presentdisclosure;

FIG. 10B is a diagram of a single-ping algorithm for receiver typedetection, in accordance with an exemplary embodiment of the presentdisclosure;

FIG. 11 is a diagram of a multi-ping algorithm for receiver typedetection, in accordance with an exemplary embodiment of the presentdisclosure;

FIG. 12 shows one of the possible types of waveforms of the receivecommunication and transmit coil voltage during communication;

FIG. 13 is a diagram of a demodulation algorithm, in accordance with anexemplary embodiment of the present disclosure;

FIG. 14 is a diagram of a system for processing data, in accordance withan exemplary embodiment of the present disclosure;

FIG. 15 shows one of the possible types of waveforms of the receivecommunication and transmit coil voltage during communication;

FIG. 16 is a diagram of amplitude modulation, in accordance with anexemplary embodiment of the present disclosure;

FIG. 17 is a diagram showing frequency modulation, in accordance with anexemplary embodiment of the present disclosure; and

FIG. 18 is a diagram of a circuit for providing a capacitive grid thatcan be used to detect metallic objects, in accordance with an exemplaryembodiment of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

In the description that follows, like parts are marked throughout thespecification and drawings with the same reference numerals. The drawingfigures might not be to scale and certain components can be shown ingeneralized or schematic form and identified by commercial designationsin the interest of clarity and conciseness.

The word “exemplary” is used herein to mean serving as an example,instance, or illustration. Any aspect or design described herein as“exemplary” is not necessarily to be construed as preferred oradvantageous over other aspects or designs. Further, for the purposes ofthis disclosure and unless otherwise specified, “a” or “an” means “oneor more”. Still further, the use of “and” or “or” is intended to include“and/or” unless specifically indicated otherwise.

The present disclosure is directed to a device for transferring powerand data that can detect and use multiple different data standards andprotocols, so as to be usable with different devices from differentmanufacturers. The disclosed multi-standard device includes aprogrammable controller that receives and processes data that can beencoded using any of one or more different standards or protocols, andhas components that are used to transmit and receive power signals, datasignals or a suitable combination of both, using electromagneticradiation, magnetic flux or a suitable combination of energy sources.The multi-standard device can determine a data or power transmissionstandard or protocol that is being used by another device through thedisclosed algorithmic processes, and can adjust its operating functionsto allow it to interact using the detected standards or protocols.

The disclosed system can use multiple protocols to accomplish power ordata transfer, where at least one of the devices can operate undermultiple uses, such as under different standards, under different poweror data protocols, under different distance protocols, under differentsafety conditions and so forth. In one exemplary embodiment, the deviceof the present disclosure is configured to interoperate with anotherdevice capable of only operating under a single standard, protocol oruse mode.

In the description that follows, like parts are marked throughout thespecification and drawings with the same reference numerals,respectively. The drawing figures might not be to scale and certaincomponents can be shown in generalized or schematic form and identifiedby commercial designations in the interest of clarity and conciseness.

FIG. 1A is a diagram of a system 100 for wireless power and datatransmission in accordance with an exemplary embodiment of the presentdisclosure. System 100 includes programmable controller 104, outputstage and matching network 106 and bridge and matching network 116(which form a power stage capable of transmitting power and data acrossthe interface to a load 122), power supply 102, a resonant antennasystem that includes capacitors 108 and 114 and inductors L_(P) 110 andL_(S) 112, control and communication circuit 118 and regulator 120,which are used to measure voltages and currents in the system. Componentvalues for the circuitry are chosen to provide system operation acrosspredetermined standards and application requirements supported by thedevice.

In operation, a primary transceiver such as output stage and matchingnetwork 106 monitors the region around an antenna, such as usingcapacitor 106 and inductor L_(P) 110, to determine when a secondarytransceiver such as bridge and matching network 116 is nearby, such asby measuring a change in impedance at a predetermined frequency, inducedvoltages or other suitable signals. Once the proximity of a secondarytransceiver is detected, the primary transceiver transmits apredetermined amount of power to energize the secondary transceiver,which can be referred to herein as the “ping” phase. After the secondarytransceiver begins operation, the primary transceiver and secondarytransceiver transmit and receive data to in accordance with one or morealgorithms to exchange identification and to select a protocol to usefor power and data transfer. One method for transmitting and receivingdata is by use of bi-directional communication through amplitude loadmodulation, frequency modulation, RF, infrared or other light-basedsignaling, or other suitable methods.

The secondary transceiver can be protected from over-voltage by changinga resonant state of a tunable circuit, such as that formed by capacitor114 and inductor L_(S) 112, by switching capacitance elements into orout of the tunable circuit. FIG. 1B is a diagram of different exemplarytopologies for protecting a wireless power receiver from over-voltagesusing the de-tuning of the resonant circuit to keep the rectifiedvoltage to safe levels. In one exemplary embodiment, the tunable circuitcan include a sensor (such as within bridge and matching network 116,control and communication circuit 118, regulator 120 or other suitablecircuits) that senses an AC voltage at an input to a bridge rectifier,such as bridge rectifier 130, and when that voltage reaches apre-determined level, the sensor and associated control circuitry canconnect or disconnect one or more capacitive elements to change theresonant frequency of the tunable circuit from the transmitter frequencyof the primary transceiver, thereby reducing the energy in the receivercoil. For example, secondary transceiver 124 can include resistor 180and transistor 132, which switches capacitor 134 in or out of serieswith capacitor 136, as a function of the state of transistor 140, whichis turned on or off as a function of a voltage drop across resistor 144driven by diode 142 and a corresponding voltage drop across resistor 138when transistor 140 is on or off.

In another exemplary embodiment, secondary transceiver 126 can includeswitch 148, which switches capacitor 146 in and out of series withcapacitor 114 as a function of the state of transistor 150, which iscontrolled by a voltage drop across resistor 152 that is driven by diode154. An exemplary detail diagram of switch 148 is shown by transistors166 and 168, which have a common gate and center connection to lowvoltage through 170.

In another exemplary embodiment, secondary transceiver 128 can includecapacitors 156 and 160, which are switched in and out of series withcapacitor 114 by transistors 158 and 162. Likewise, other suitableconfigurations can also or alternatively be used.

FIG. 2 is a diagram of an exemplary wireless power receiver 200 toprotect a resonant wireless power receiver from over-voltages byshorting the coil to keep the rectified voltage to safe levels. Wirelesspower receiver 200 includes bridge rectifier 202, a resonant antennasystem formed by inductance 204 and capacitance 206, controller 208,which is configured to sense a magnitude of an AC input voltage acrossinductance 204, and switch 210, which connects and disconnects acapacitive element 214. The resonant antenna system can be attenuated bydetuning through changing the center frequency of the LC circuit, byreducing the gain, by lowering the resistance value or in other suitablemanners. Controller 208 includes a voltage sensing mechanism on thesecondary side of the rectifier, and can be configured such that whenthe sensed voltage reaches a predetermined threshold, a feedbackmechanism is enabled to adjust the capacitive value to detune theresonant antenna system, to adjust a capacitor divider which bothreduces gain and detunes the output, or which performs other suitablefunctions. Other implementations of this type of feedback mechanism canbe used to adjust gain, alter a resonant frequency, or to implementother suitable functions.

Implementations of wireless power receiver 200 can use a suitablefeedback mechanism with active components, passive components,capacitive elements, inductive elements, resistive elements or othersuitable elements, circuits or systems.

FIG. 3 is a diagram of a system 300 for providing a full-synchronousbridge as a rectifier in wireless power circuits, in accordance with anexemplary embodiment of the present disclosure. The full-synchronousbridge can be used to protect the wireless power receiver fromover-voltages by changing the switching angle of the bridge away fromthe current zero-crossing point without the need for additionalcomponents. System 300 changes a switching angle of a switching bridge316 away from the current zero crossing point. For example, whenswitching bridge 316 is switching transistors 306, 308, 310 and 312 whenthe current is synchronous with the input AC waveform, 100% of thecurrent I_(C) generated in the resonant circuit flows into the storagecapacitor 314, increasing its voltage. By moving the switching pointaway from the zero-crossing of the AC waveform, a portion of the currentflows from storage capacitor 314 back into the resonant circuit formedby inductor 302 and capacitor 304, reducing the capacitor voltage.Shifting the bridge switching point 90 degrees from the current zerocrossing point causes an equal amount of current to flow into and out ofthe storage capacitor 314 as the bridge switches 306, 308, 310 and 312,keeping the capacitor voltage constant. Dynamically moving the bridgeswitching point allows system 300 to prevent a voltage V_(PEAK) fromexceeding a predetermined threshold and to maintain that voltage untilthe energy in the resonant circuit dissipates to a safe level.

In one exemplary embodiment, a voltage sensing mechanism can be used ona secondary side of the rectifier. Once the sensed voltage reaches apredetermined threshold, a feedback mechanism can be enabled to changethe switching point for the synchronous rectifier. When the secondaryvoltage falls below the threshold, the feedback mechanism can move theswitching point to a previous operating point or other suitable points.

FIG. 4 is a diagram 400 of current and timing waveforms, in accordancewith an exemplary embodiment of the present disclosure. Diagram 400includes current waveform I_(C), which has zero crossing points thatcorrelate to the transition times of a clock signal V_(Q). By shiftingclock switching times to the waveform shown as V_(Q′), it can be seenthat a period of time in which I_(IN) switches to I_(OUT) for system 300is created.

FIG. 5 is a diagram of a system 500 that is configured to resonate attwo different frequencies, in accordance with an exemplary embodiment ofthe present disclosure. System 500 measures the DC voltage and currentat the rectifier 504 output, and controller 502 causes switches S1through Sn to switch capacitive elements C1 through Cn in parallel andseries with the exemplary inductances and capacitance as shown, tocontrol the power output of the rectifier to load elements 506A and506B. The number of capacitive elements and corresponding switches canbe used to control the tunable range and accuracy of system 500.Alternatively, other types of passive devices can be used for tuning andgain adjustment such as resistors, inductors, capacitors and others.

In a resonant system, both the transmitting and receiving entities canbe tuned so that both sides resonate at the same frequency, thusmaximizing power transfer. Tuning can be accomplished by switchingcapacitive elements into or out of the antenna circuits usinghigh-bandwidth low-loss switches. The DC current of an associated bridgerectifier output can be measured using a current sense amplifier or inother suitable manners, and the current measurement can then bemaximized by switching capacitive elements into or out of the resonatingcircuit, or in other suitable manners.

FIG. 6 is a diagram of a system 600 with a step-down DC/DC switchingconverter, in accordance with an exemplary embodiment of the presentdisclosure. Buck DC/DC switching converter 606 regulates the output ofrectifier bridge 604 to the load. The measurement of output currentI_(OUT) can performed at the output of buck 606, rather than at theoutput of rectifier 604, and this current measurement can be used in thetuning algorithm that chooses the tuning and gain adjustment elements toswitch in to or out of the circuit formed by capacitors C1 through Cnand the other exemplary capacitive and inductive elements as shown.Alternatively, controller 602 can provide step-up control, step-downcontrol, linear control, a combination of switching and linear controlor other suitable controls. Switching tuning capacitor elements C1through Cn or other suitable elements in the resonant circuit of system600 can also or alternatively be used to increase the transmitter toreceiver antenna-to-antenna separation range on a magnetic inductionpower transfer system by tuning the receiver to a resonance mode, as afunction of the transmitter frequency.

FIG. 7 is a diagram of a system 700 with a passive resonator that actsas a repeater in a magnetic resonant power transfer system, inaccordance with an exemplary embodiment of the present disclosure. Thepassive resonator of system 700 is constructed similar to the primarytransmitter resonant antenna circuit. System 700 can be located within amagnetic flux field generated by an active transmitter, which can thenbe excited by that magnetic field to enable power and data transfer overa broader spatial range than in a system with a non-resonant transmitterantenna alone. Tuning controller 710 can be powered by a captive supply,by scavenging energy from the power transfer system or in other suitablemanners. System 700 can be tuned to resonate at a frequency of atransmitter by switching capacitive elements 708A through 708N as afunction of measured current or power. By maximizing the measuredcurrent or power, a tuning algorithm can choose the correct combinationof capacitive elements 708A through 708N to include in the resonantcircuit. For example, a simple search algorithm can be implemented thatstarts with the lowest capacitance value for the combination ofcapacitors, and which then increases the capacitance value by thesmallest next step, until a peak measured current or power is detected,such as by comparing a current or power measurement from a prior settingto a current or power measurement for a present setting, and stoppingthe search process when the current or power measurement starts todecrease. In another exemplary embodiment, a binary search algorithm, alinear search algorithm, an asymptotic search algorithm, a geometricsearch algorithm, or other suitable search algorithms can also oralternatively be utilized.

FIG. 7 is a diagram of a system 700 with a passive resonator that actsas a repeater in a magnetic resonant power transfer system, inaccordance with an exemplary embodiment of the present disclosure. Thepassive resonator of system 700 is constructed similar to the primarytransmitter resonant antenna circuit, and includes inductor 702,capacitors 704 and 706 and resistor 712. System 700 can be locatedwithin a magnetic flux field generated by an active transmitter, whichcan then be excited by that magnetic field to enable power and datatransfer over a broader spatial range than in a system with anon-resonant transmitter antenna alone. Tuning controller 710 can bepowered by a captive supply, by scavenging energy from the powertransfer system or in other suitable manners. System 700 can be tuned toresonate at a frequency of a transmitter by switching capacitiveelements 708A through 708N as a function of measured current or power.By maximizing the measured current or power, a tuning algorithm canchoose the correct combination of capacitive elements 708A through 708Nto include in the resonant circuit. For example, a simple searchalgorithm can be implemented that starts with the lowest capacitancevalue for the combination of capacitors, and which then increases thecapacitance value by the smallest next step, until a peak measuredcurrent or power is detected, such as by comparing a current or powermeasurement from a prior setting to a current or power measurement for apresent setting, and stopping the search process when the current orpower measurement starts to decrease. In another exemplary embodiment, abinary search algorithm, a linear search algorithm, an asymptotic searchalgorithm, a geometric search algorithm, or other suitable searchalgorithms can also or alternatively be utilized.

FIG. 8 is a diagram a class E transmitter 800, in accordance with anexemplary embodiment of the present disclosure. Class E transmitter 800can be used to transmit power to a low-frequency magnetic inductionreceiver, a higher-frequency electro magnetic resonance receiver orother suitable receivers. In this exemplary embodiment, class Etransmitter 800 has two different antenna elements—a 0.5 uH inductiveelement for low frequency signals, and a 24 uH inductive element forhigh frequency signals, but other suitable circuit elements can also oralternatively be used. Also shown are transistor 802, resistor 804,capacitor 806, capacitor 808, diode 810, diode 812 and capacitor 814.

FIG. 10A is a diagram 1000 of exemplary waveforms for receiver typedetection, in accordance with an exemplary embodiment of the presentdisclosure. The PMA RX signal is an exemplary communication from a PMAreceiver. The Qi receiver signal is an exemplary communication from a Qireceiver. The transmitter power signal is an exemplary presence ofwireless power (ping sequence) as a sine wave of a high frequency. Innormal operation, only one of the receivers will be sending the signal.The transmitter selects the standard used by the receiver by looking atthe communication during the ping sequence.

FIG. 10B is a diagram of a single-ping algorithm 1002 for receiver typedetection, in accordance with an exemplary embodiment of the presentdisclosure. Algorithm 1002 can be implemented in hardware or a suitablecombination of hardware and software.

As used herein, “hardware” can include a combination of discretecomponents, an integrated circuit, an application-specific integratedcircuit, a field programmable gate array, or other suitable hardware. Asused herein, “software” can include one or more objects, agents,threads, lines of code, subroutines, separate software applications, twoor more lines of code or other suitable software structures operating intwo or more software applications, on one or more processors (where aprocessor includes a microcomputer or other suitable controller, memorydevices, input-output devices, displays, data input devices such as akeyboard or a mouse, peripherals such as printers and speakers,associated drivers, control cards, power sources, network devices,docking station devices, or other suitable devices operating undercontrol of software systems in conjunction with the processor or otherdevices), or other suitable software structures. In one exemplaryembodiment, software can include one or more lines of code or othersuitable software structures operating in a general purpose softwareapplication, such as an operating system, and one or more lines of codeor other suitable software structures operating in a specific purposesoftware application. As used herein, the term “couple” and its cognateterms, such as “couples” and “coupled,” can include a physicalconnection (such as a copper conductor), a virtual connection (such asthrough randomly assigned memory locations of a data memory device), alogical connection (such as through logical gates of a semiconductingdevice), other suitable connections, or a suitable combination of suchconnections.

At 1004, a transmitter broadcasts a ping compatible with multipleprotocols, such as the TX POWER waveform. The transmitter can beoperated by a suitable controller, such as by using digital controlsfrom a programmable controller, an application-specific integratedcircuit, a field programmable gate array or other suitable devices. Thealgorithm then proceeds to 1006.

At 1006, one or more receiver responses are detected, such as the PMA orQi waveforms of FIG. 10A or other suitable responses. The responses canbe detected by monitoring a voltage detected at a receiver circuit or inother suitable manners. The algorithm then proceeds to 1008.

At 1008, it is determined whether a response in accordance with a firststandard has been received, such as by comparing a measured voltage to afirst voltage waveform stored in memory or in other suitable manners. Ifa response in accordance with the first standard has been received, thealgorithm proceeds to 1012, where a first power or data transfer phasesetting is implemented, such as by selecting a first predeterminedswitch setting for capacitive element control switches, as discussedherein, or in other suitable manners. Otherwise, the algorithm proceedsto response 1010.

At 1010, it is determined whether a response in accordance with a secondstandard has been received, such as by comparing a measured voltage to asecond voltage waveform stored in memory or in other suitable manners.If a response in accordance with the second standard has been received,the algorithm proceeds to 1012, where a second power or data transferphase setting is implemented, such as by selecting a secondpredetermined switch setting for capacitive element control switches, asdiscussed herein, or in other suitable manners. Otherwise, the algorithmreturns to 1004. Likewise, other suitable detection processes can beused for other suitable standards.

Based on the detected data, the transmitter adjusts its transmissionconfiguration to complement the detected receiver protocol. A truemulti-mode wireless power transmitter can be constructed to dynamicallychange its operating point according to the protocol of the receiverpresented. The transmitter can interrogate the receiver by broadcastinga ping and receiving a response that informs the transmitter the type ofreceiver that is present. A single ping that works for more than onestandard, multiple pings that each correspond to a different standard,or other suitable processes can also or alternatively be used.

FIG. 11 is a diagram of a multi-ping algorithm 1100 for receiver typedetection, in accordance with an exemplary embodiment of the presentdisclosure. Algorithm 1002 can be implemented in hardware or a suitablecombination of hardware and software.

Algorithm 1100 begins at 1102, where a transmitter broadcasts a separateping for a first standard or protocol. In one exemplary embodiment, thetransmitter can be connected to a controller using a digital datacommunications medium, and can receive one or more digital controls thatcause associated circuitry to generate a first waveform, or othersuitable processes can also or alternatively be used. The algorithm thenproceeds to 1104.

At 1104, the controller monitors signals generated by a receiver for aresponse. In one exemplary embodiment, the controller can be connectedto the receiver using a digital data communications medium, and cantransmit one or more analog or digital controls that are processed bythe controller to detect a response, such as by comparing the receivedsignal to an allowable received signal or in other suitable manners. Thealgorithm then proceeds to 1106.

At 1106, it is determined whether a correct response was received. If acorrect response was not received, the algorithm proceeds to 1108,otherwise the algorithm proceeds to 1114, where a power or data transferphase is selected to adjust a transmission configuration to complementthe receiver requirement.

At 1108, a transmitter broadcasts a separate ping for a second standardor protocol. The algorithm then proceeds to 1010, where the controllermonitors signals generated by a receiver for a response. The algorithmthen proceeds to 1112.

At 1112, it is determined whether a correct response was received. If acorrect response was not received, the algorithm returns to 1102,otherwise the algorithm proceeds to 1114, where a power or data transferphase is selected to adjust a transmission configuration to complementthe receiver requirement.

The single-ping or multi-ping algorithm can be used for both magneticinduction and magnetic resonance systems. Alternatively, the receivercan broadcast data to the transmitter, and upon receiving a response,change its configuration to match the capability of the transmitter.Alternatively, the device may be a transceiver that interrogates througha ping to adjust its configuration to be either a transmitter orreceiver, and what type of protocol the complementary device cansupport. Additionally, other elements can be adjusted, such as power,voltage, foreign object detection characteristics, thermal requirements,data rate, and physical antenna separation.

In order to manage and ensure safe voltages at the receiver-rectifiedvoltage during a transmitter ping phase, the configuration of thetransmitter bridge can be switched during an initial ping and receiverwake-up period. For a wireless power protocol or standard that requireshigher voltages for receiver wake-up, the transmitter power section canbe started in a half-bridge configuration for the initial ping(s). Ifthe half-bridge pings are not sufficient to wake up the receiver, thenthe bridge can be configured in full-bridge mode at an appropriate dutycycle. This algorithm also allows the half-bridge and full-bridge pingsto be performed at the same frequency, in order to comply with standardsrequirements. This bridge switching behavior allows true multi-standardtransmitter operation with a wide variety of receiver configurations,while simultaneously ensuring safe voltage levels on the receiver toprevent damage.

For demodulating the communication from the receiver to transmitter in amagnetic inductive system, such as one that conforms to the PowerMatters Alliance (PMA) standard, the transmit coil voltage waveform issampled. Multiple samples are taken during a first period and are storedin a buffer. The values of these samples are compared to samples takenat previous periods. If the samples of the current period are differentthan the previous samples, then a demodulation algorithm can trigger achange in a transmit state, which can direct a control algorithm tomeasure a pulse between disturbances. The length of this pulse can beused to determine whether to increase or reduce the current into thetransmit coil, and therefore the power output of the transmitter.

FIG. 12 shows one of the possible types of waveforms of the receivecommunication and transmit coil voltage during communication. Theperiodic waveform of the transmitter coil voltage is disturbed by acommunication pulse sent by the receiver. The waveform looks similar toa sine wave before the pulse but gets distorted to a random waveform fora certain period of time after the pulse, after which it slowly recoversand comes back to the sine-like waveform.

FIG. 13 is a diagram of a demodulation algorithm 1300, in accordancewith an exemplary embodiment of the present disclosure. Algorithm 1300can be implemented in hardware or a suitable combination of hardware andsoftware.

Algorithm 1300 can be used for demodulating a communication from areceiver to a transmitter in a magnetic inductive system, such as onethat conforms to the Wireless Power Consortium (Qi®) standard, wheresub-Nyquist sampling of the transmit AC coil voltage is performed at aparticular frequency, and which is then averaged in order to determineamplitude and phase changes on the carrier.

Algorithm 1300 begins at 1302, where a receiver modulates acommunication link. In one exemplary embodiment, the receiver can becoupled to a digital controller and can receive one or more digitalcontrol signals that cause the communications link to be modulated inaccordance with one or more frequency or data parameters. The algorithmthen proceeds to 1304.

At 1304, the transmitter samples the communications link, such as byreceiving one or more analog samples and by converting the analogsamples to digital values, or in other suitable manners. The algorithmthen proceeds to 1306.

At 1306, the sampled data is processed, such as by storing the data in abuffer or in other suitable manners. The algorithm then proceeds to1308.

At 1308, the transmitter processes the buffered data, such as bycomparing the buffered data to data from a previous period, to a storedwaveform or in other suitable manners. The algorithm then proceeds to1310.

At 1310, it is determined whether a valid communication has beendetected. If a valid communication has not been detected, the algorithmreturns to 1302, otherwise the algorithm proceeds to 1312.

At 1312, the transmitter changes an operating point.

FIG. 14 is a diagram of a system 1400 for processing data, in accordancewith an exemplary embodiment of the present disclosure. System 1400includes analog to digital converter 1402 and averager 1404. Thesampling points input into analog to digital converter 1402 are taken atpredetermined points on an input waveform. Because the systemcontinuously samples these known points, it requires less sampling andprocessing resources to perform the demodulation, which reduces theoverall complexity and cost of the system. An averager can generateaverage value data for determining amplitude or phase changes.

FIG. 15 shows one of the possible types of waveforms of the receivecommunication and transmit coil voltage during communication.

In a wireless power transfer system, bi-directional communicationbetween a receiver and transmitter can be used for multiple purposes.Data transfer between the receiver and transmitter can be used tocommunicate system status and capability of each side of the interface,to ensure the transfer is accomplished at the highest efficiency andshortest charging times. Similarly, this communication can be used toaid in the detection of foreign metallic objects within the magneticfield, for receiver and transmitter authentication to ensure that onlycompatible devices are connected, for financial transactions betweenreceiver and transmitter to enable pay-for-charging in publicinfrastructure applications, for the transmitter and receiver tonegotiate the maximum power to be transferred in the system, to pushadvertisements to an end user, to transfer application data between areceiver and a transmitter, or for other suitable purposes.

FIG. 16 is a diagram of amplitude modulation, in accordance with anexemplary embodiment of the present disclosure. The frequency of thesine wave can be increased slightly to fit more cycles inside eachstable level of the receiver waveform. The frequency is the same, butthe amplitude changes based on the receiver level.

FIG. 17 is a diagram of frequency modulation, in accordance with anexemplary embodiment of the present disclosure. As shown in FIG. 17, theamplitude is the same, but the frequency is higher or lower. Thereceiver demodulates the signal and obtains levels of zero or one.Alternatively, this application can be used for power banks, “Internetof Things” (IoT) appliances, autonomous systems, medical/bodymonitoring, passive electronic systems such as credit cards or othersuitable applications.

In order to regulate the output voltage of the wireless power receivingentity, a periodic communication signal can be asserted on the receiverresonant circuit. This periodic signal can be generated with a simplelow-cost analog circuit to save cost and board space. The signalfunctions as the “heartbeat” of the system, and can signal both the needfor the transmitter or receiver to change its operation point orfunction. Alternatively, the signal can be used for the transmitter toidentify both the presence of a receiver and to authenticate a receiver,to control the function of the transmitter from the receiver, to signalto a transmitter when a receiver has an error condition or has beenremoved, to transfer encoded or unencoded data between two entities, orfor other suitable purposes. A combination of amplitude and frequencycan be used for this type of “heartbeat” communication, PSK or FSK canbe used for this type of “heartbeat” communication, or other suitabledata can also or alternatively be used.

FIG. 18 is a diagram of a circuit 1800 for providing a capacitive gridthat can be used to detect metallic objects, in accordance with anexemplary embodiment of the present disclosure. Circuit 1800 includesleads L1 through L6, which are each coupled to a pair of capacitors.Other sensing arrays or grids can be used with other passive or activedevices. Also shown is capacitors 1802-1818.

Foreign metallic objects can be detected within the magnetic field of awireless power transfer system using an array of capacitive sensorsplaced above or near the transmit antenna. The capacitive sensors can bearranged in an X-Y grid so they can be combined into rows and columns toreduce the number of connections to the control circuitry. When a changeis detected in one or more of the capacitive sensors, a foreign objectis detected in the field and the transmitter can act appropriately.

Similarly, foreign metallic objects can be detected within the magneticfield of a multi-mode magnetic inductive and magnetic resonant wirelesspower transfer system using the inactive antenna. If the magneticinductive interface is active, a change in the impedance of the magneticresonant antenna would signal that a foreign object has entered themagnetic field and the transmitter can act appropriately. Likewise, themagnetic inductive antenna could be used to sense objects in themagnetic resonant field when active.

The receiver coil and bridge rectifier in a wireless power receiver canalso be used to emulate a synchronous step-up (boost) circuit toincrease the voltage output of the rectifier. Similarly, the receivercoil and bridge rectifier in a wireless power receiver can also be usedto emulate a synchronous step-down (buck) circuit to decrease thevoltage output of the rectifier.

It should be emphasized that the above-described embodiments are merelyexamples of possible implementations. Many variations and modificationsmay be made to the above-described embodiments without departing fromthe principles of the present disclosure. All such modifications andvariations are intended to be included herein within the scope of thisdisclosure and protected by the following claims.

What is claimed is:
 1. A wireless device comprising: an antenna systemcomprising at least one inductive element and two or more capacitiveelements; a switching component configured to change a circuitconfiguration of the capacitive elements; and a controller configured totransmit a signal using the antenna system and to receive a responsefrom a first device, to determine a communications protocol associatedwith the first device and to change a configuration of the antennasystem in response to the determined communications protocol byactuating the switching component, wherein the controller is configuredto transmit a first signal in accordance with a first protocol and towait a predetermined period of time for a response, and then to transmita second signal in accordance with a second protocol if no response isreceived.
 2. The wireless device of claim 1 wherein the controller isconfigured to detect whether the first device is within proximity to thecontroller and to transmit the signal in response to the detection. 3.The wireless device of claim 1 wherein the controller is configured totransmit additional signals in accordance with additional protocolsuntil a response is received.
 4. A wireless device of claim 1 whereinthe controller is configured to maximize a power transfer or efficiencyby tuning a transmitting entity and a receiving entity to each resonateat a frequency.
 5. The wireless device of claim 1 wherein the switchingcomponent comprises one or more high-bandwidth, low-loss switches, andfurther comprising a device configured to measure one of a voltage, acurrent or a power in the device, and wherein the controller isconfigured to actuate the switches as a function of the measuredvoltage, current or power in the device.
 6. The wireless device of claim1 wherein the controller is configured to transmit a signal that cangenerate a response in accordance with multiple different protocols. 7.A method comprising: transmitting a signal to an antenna systemcomprising at least one inductive element and two or more capacitiveelements; receiving a response from a first device at a controller;determining a communications protocol associated with the first deviceat the controller; and changing a configuration of the antenna system atthe controller in response to the determined communications protocol byactuating a switching component configured to change a circuitconfiguration of the capacitive elements; transmitting a first signal inaccordance with a first protocol from the controller; waiting apredetermined period of time for a response; and transmitting a secondsignal in accordance with a second protocol from the controller if noresponse is received.
 8. The method of claim 7 further comprising:detecting whether the first device is within proximity to thecontroller; and transmitting the first signal in response to thedetection.
 9. The method claim 7 further comprising transmittingadditional signals in accordance with additional protocols until aresponse is received.
 10. The method of claim 7 further comprisingmaximizing a power transfer or efficiency by tuning a transmittingentity and a receiving entity to each resonate at a frequency.
 11. Themethod of claim 7 further comprising transmitting a signal that cangenerate a response in accordance with multiple different protocols. 12.The method of claim 7 further comprising detecting whether the firstdevice is within proximity to the controller.
 13. The method of claim 7further comprising: measuring one of a voltage, a current or a power inthe first device; and actuating the switching component as a function ofthe measured voltage, current or power in the first device.
 14. Themethod of claim 13 wherein the switching component comprises one or morehigh-bandwidth, low-loss switches.
 15. The method of claim 7 furthercomprising: measuring one of a voltage, a current or a power in thefirst device; and actuating the switching component after measuring. 16.The method of claim 15 wherein the switching component comprises one ormore high-bandwidth, low-loss switches.